The present invention relates to a method and apparatus for assembling a door, especially a multi-panel door. The method and apparatus of the present invention are particularly suited to manufacture of a multi-panel wooden door.
Wooden doors have been manufactured and sold for many years and have classic, accepted designs well-known in the industry. A particularly well-known design is the classic six-panel door which provides a plurality of rails (horizontally oriented bar members), a plurality of mullions (vertically oriented bar members intermediate the rails), and stiles (vertically oriented side members affixed substantially along the full length of the assembled door). Thus, a standard six-panel door will include four rails, three mullions, two stiles, and six panels. The six panels are engaged intermediate a respective pair of rails in a vertical axis, and intermediate a respective mullion and a respective stile in a horizontal axis. Preferably, the panels are only nestingly engaged with their adjacent rails, mullion, and stile in a manner which allows them to "float" to accommodate expansion and contraction of the wooden adjacent members (i.e., adjacent rails, mullion, and stile) with changes in temperature and humidity.
In the past such six-panel doors have been manufactured by hand one at a time by assembling the various panels, mullions, rails, and stiles at a single assembly operation and pressing them together. The various components which are fixed with respect to each other employ various affixation methods, such as dowels and adhesives, threaded fasteners, or other fastening methods. Dowels and adhesives have been used, for example, to affix the stiles to the remainder of the door, maintaining pressure among the various components of the door until the adhesive is sufficiently set, and then removing the finished door from the one-at-a-time assembly frame to begin another subsequent one-at-a-time assembly operation for a next door.
The benefits of in-line assembly for various mechanical operations ranging from automotive assembly to other mechanical assemblies have long been known in the art of manufacture. However, no one to date has applied in-line assembly techniques to manufacture of a multi-panel door. To preposition sufficient components (i.e., rails, mullions, panels, and stiles) at appropriate locations along an assembly line, and provide automated feeding mechanisms for selecting appropriate such components to assemble sub-assemblies of a door are novel advances in multi-panel door manufacturing. To position those subassemblies of the finished door in appropriate locations along the assembly line for subsequent incorporation into a completed door as the several sub-assemblies progress along the assembly line via a conveyor system all contribute to efficiencies advantageously and uniquely employed by the present invention to efficiently assembly multi-panel doors, especially six-panel wooden doors.
Other door designs are equally amenable to construction by in-line assembly methods and apparata. For example, two-, three-, and four-panel doors may be constructed in such a manner and with such equipment. Such door designs may, for example, employ only rails, panels, and stiles, and no mullions.
There is a need for such greater efficiency in assembling multi-panel doors, especially six-panel wooden doors.